The Pew Forum reports that fewer than 20% of people age 18 to 29 attend church services regularly, but about three-quarters of them believe in an afterlife -- about the same rate as older generations.

That would be one way to read a new report by the respected Pew Forum on Religion and Public Life, which found that more than one-quarter of Americans age 18 to 29 have no religious preference or affiliation, and fewer than one in five attend services regularly. That makes them easily the least religious generation among Americans alive today, perhaps the least religious ever.

Or does it?

The Pew study found that, although young adults -- the so-called Millennial generation born after 1981 -- are shunning traditional religious denominations and services in unprecedented numbers, their faith in God and the power of prayer appears nearly as strong as that of young people in earlier generations.

"If you think of religion primarily as a matter of whether people belong to a particular faith and attend the worship services of that faith . . . then millennials are less religious than other recent generations," said Alan Cooperman, associate director of research for the Pew Forum, a Washington-based think tank run by the nonprofit Pew Research Center. "But when it comes to measures not of belonging but of believing, they aren't so clearly less religious."

The report, "Religion Among the Millennials," relied on surveys that Pew and other research organizations have done since the 1970s, and compared the Millennial generation to four previous generations, which it labeled and defined as Gen Xers, born from 1965 to 1980; Baby Boomers, born from 1946 to 1964; the Silent Generation, 1928 to 1945; and the Greatest Generation, born before 1928. The report shows steady erosion in religious affiliation from generation to generation. All but 5% of the oldest group reported an affiliation with some religious tradition, whereas 20% of Gen Xers and 26% of today's young adults said they had no such ties.

"Millennials are coming of age less affiliated than any recent U.S. generation," Cooperman said. "And . . . I would say there's no reason to think that they're going to become more affiliated."

Although participation in religious activities and belief in God tend to increase with age, affiliation with a religious faith appears to stay largely the same, he said.

The report does show sharp differences in religious belief among generations. In one 2008 survey, just 53% of young adults said they were certain that God exists, compared to 71% of the oldest group. And although faith does tend to grow with age, recent generations have not reached quite the same levels of belief as their predecessors. Interestingly, though, there is almost no difference among the generations when it comes to other markers of religious faith. Roughly three-quarters of Americans believe in an afterlife, for instance, and there is little difference among people of different ages. Even more people -- 79% -- believe in miracles, and again, young people are just as likely as their elders to hold that view.

The Pew study shows significant differences in belief and practice among religious denominations. It tracks a decline in younger members of mainline Protestant denominations, such as Presbyterians, Episcopalians and Methodists, while African American and evangelical Protestant groups have stronger affiliation among the young.

Alexander Astin, a professor emeritus of education at UCLA who has studied the attitudes of college students since 1966, said the conclusions of the Pew study largely mirror what he has found about the religious views of young people.

"You have very high rates of skepticism and nonbelief among unaffiliated people," Astin said.

But evangelical Christians have very high levels of belief in God and participation in church activities, and their numbers are grow- ing.

So, he said, "The nonbelievers have increased, but so have the believers. So the net result of that is probably not a great change in the proportion of people who believe in God."